Dressing mechanism



April 27, 1943. H. N. sEYFERTH DRESSING MECHANISM 4 Sheets-Sheet l FiledNov. 8, 1941 ffaro April 27, 1943. H. N. sEYFERTH DRESSING MECHANISMFiled Nov. 8, 1941 4 Sheets-Sheet 2 fizzle/dor www YW April 27, 1943. H.N. SEYFERTH 21,317,411

DRESSING MECHANISM Filed NOV. 8, 1941 4 Sheet-Sheet 5 /Ig V 5k///////////////////////////// mmf-0f @www3/fsf@ April 27, 1943.

H. N. SEYFERTH DRESSING MECHANISM Filed NOV. 8, 1941 4 Sheets-Sheet 4Patented Apr. 27, 1943 DRESSING NIECHANISM Harold N. Seyferth, EastDetroit, Mich., assignor to Ex-Cell-O Corporation, Detroit, Mich., acorporation of Michigan Application November 8, 1941, Serial No. 418,299

(Cl. 12S-11) 19 Claims.

The present invention relates to improvements in dressing mechanisms forgrinding wheels.

One of the objects of the present invention is to provide a noveldressing mechanism having at least one dressing tool arranged todescribe a path of movement in one direction for dressing one ank of agrinding rib, and to describe a similar path of movement displaced fromsaid first-mentioned path in the return direction to dress the otherflank of the rib.

Another object is to provide a new and improved dressing mechanismhaving a dressing tool arranged to describe similar but displaced pathsof movements in opposite directions, and having means for adjusting thedegree of displacement of said paths so as to obtain ribs of differentwidths but with the same included angle.

A further object is to provide a novel dressing mechanism of theforegoing character having a reversible drive, including a followermechanism arranged for -adjustment as an incident to reversal of thedrive to effect clearance between the tool and the grinding wheel duringa portion of the dressing movement in each direction.

Still another object is to provide a new and improved dressing mechanismhaving a dressing tool, and reversible drive means effective totranslate the dressing tool in one direction through a cutting path andupon reversal at any point in said path to retract said tool fromengagement with the previously dressed surface.

Further objects and advantages will become apparent as the descriptionproceeds.

In the accompanying drawings:

Figure 1 is a plan view, with the cover removed,

of a dressing mechanism embodying the features of my invention.

Fig. 2 is an end elevational view of the dressing mechanism.

Fig. 3 is a vertical sectional view taken along line 3 3 of Fig. 2.

Fig. 4 is a vertical sectional view taken along line 4-4 of Fig. 3.

Fig. 5 is ahorizontal sectional view taken along line 5 5 of Fig. 3.

Fig. 6 is a fragmentary plan view taken substantially along line E-G'ofFig. 3.

Fig. 7 is a diagrammatic representation illustrating the path ofmovement of the dressing tool under one condition of adjustment.

Fig. 8 is -a diagrammatic representation illustrating the path ofmovement of the dressing tool under another condition of adjustment.

Fig. 9 is a diagrammatic representation illustrating the path ofmovement of the dressing mechanism under still another condition ofoperation.

Fig. 10 is a fragmentary plan view of a modied form of dressingmechanism comprising two tools for dressing opposite iianks of agrinding Wheel rib.

Fig. 11 is a diagrammatic representation illustrating the paths ofmovement of the dressing .tools in the form of Fig. 10.

While the invention is susceptible of various modifications andalternative constructions, 1 have shown in the drawings and will hereindescribe in detail the preferred embodiment, but it is to be understoodthat I do not thereby intend to limit the invention to the specic formdisclosed, but intend to cover all modifications and alternativeconstructions falling within the spirit and scope of the invention asexpressed in the appended claims.

The dressing mechanism constituting the exemplary embodiment of theinvention comprises a main body or housing I adapted to be mounted upona suitable support in appropriate relation to a grinding wheel 2. In thepresent instance, the housing I is hollow, and has a lower section 3formed with a circular mounting flange 4 rotatably secured for angularadjustment within a yoke 5 on a dresser slide 6 adjustable toward andfrom the grinding wheel 2. A top section 1 is bolted to the section 3,and has an access opening 8 normally closed by a removable cover plate9.

Enclosed in the housing I is a composite slide assembly, consisting of aslide or carriage I3 movable in a. direction generally parallel to theaxis of the grinding wheel 2, and a tool slide I4 mounted on the slideI3 for movement therewith and also for movement thereon in a directiongenerally perpendicular to the Wheel axis. The slide I4 projects freelythrough an opening I5 in one end wall of the housing I, and carries atool holder I6 formed with a socket II to receive a single pointdressing tool I8. By reason of the independent cross movements of theslides I3 and I4, the dressing tool I8 is given a. resultant movementadapted to produce the desired cutting contour on the grinding wheel 2.

The carriage It is supported for reciprocation within the housing I bymeans of suitable ball bearings I 9, and serves to support most of theactuating parts of the dressing mechanism. Journaled in ball bearings 20in the carriage I3 is a vertical cam shaft 2l. A plurality of cams 22,23 and 24 are secured in axially spaced relation to the shaft 2i forrotation therewith. The cam 22 controls the reciprocation of thecarriage I3; the cam 2g controls the reciprocation of the slide Iii onthe carriage I3; and the'cam 24 controls the cycle of dressingoperation.

Any suitable means may be provided for driving the shaft 2i through apredetermined movement. In the present instance, this means comprises aworm wheel 25 xed on the shaft 2I intermediate the bearings 2li andmeshing with a Worm 26, The worm 26 in turn is fixed on a drive shaft 21suitably Journaled in bearings 28 and 29 within the carriage I3 andconnected at one end to a flexible shaft 3| driven by a reversibleelectric motor (not shown). The motor is controlled by a switch 33suitably mounted within the housing I.

The cam 22 coacts with a cam follower 34Y which is pivotally mountedintermediate its ends on a pin.35 within a sleeve 36 supported in andextending through a bore 31 in one wall of the housing I. The inner endof the follower 34 is formed with a V notch 38. An adjusting screw 39,with a micrometer dial 40, is threaded into the outer end of the sleeve36, and has a tapered or conical end 4I adapted for engagement in thenotch 38 to control the action of the follower upon forward and reversemovements of the cam 22. When the screw 39 is turned into its innermostposition to locate the conical end 4I tightly in the notch 38, thefollower 34 is secured rigidly in position, i. e., constrained againstpivotal movement about the pin 35. Upon loosening the screw 39 to apredetermined extent, as indicated by the micrometer 40, lost motion isintroduced between the conical end 4I and the notch 38 to permit alimited degree of oscillation of the follower 34. The amount of lostmotion, and hence the degree of oscillation, may be adjusted by varyingthe extent to which the screw 39 is turned out in accordance with therequirements of the dressing operation. Suitable springsl I3, acting onthe carriage I3, serve to maintain the cam 22 in operative engagementwith the cam follower a conical tip 49 adapted for engagement in thesocket 41. When the tip 49 is in full tight engagement with the socket41, it constrains the follower 45 against swinging movement about thepin 46. Upon loosening the screw 48, lost motion is introduced betweenthe conical tip 49 and the socket 41, and permits swinging oroscillatory movement of the follower 45 upon reversal of rotation of thecam 23. The screw 48 is loosened .more or less, depending upon thedesired degree of oscillation. Suitable springs I4*i act on the slide I4to maintain the follower 45 in operative association with the ca m 23.

The cam 24 acts through a lever 58 pivoted on the carriage I3 andarranged to actuate the switch 33. In the present instance, the cam hasan arcuate projection 5I arranged to contact the lever after slightlyless than one revolution in opposite directions. Upon actuating theelectric drive, controlled in part by the switch 33, to initiate thedressing cycle, a rotary drive will be imparted to the cam shaft 2|.Upon rotation of the shaft 2I through slightly less than one completerevolution, the cam projection 5I will engage the lever 50 to actuatethe switch 33, and thereby reverse the drive. After reverse rotationthrough the same degree of revolution, the cam projection 5I will againengage the lever 50 to actuate the switch 33 and to therebystop thedrive and terminate the cycle.

The dressing mechanism is adapted to dress a wide variety of grindingwheel forms, but has particular applicability to the dressing oftruncated thread forms, auch for example as illustrated in Figs. 7 and8. This form comprises a grinding rib 52 in the periphery of thegrinding wheel 2 and having sidenanks 83 and 54 Oppositely inclined atany desired included angle. The flanks are joined at their apex by atruncating line or end face 55 parallel to the axis of the grindingwheel.

In operation, ifl the screws 88 and 4l are tightened to lock the camfollowers 34 and 45 against oscillation, both slides or carriages I3 andI4 will move exactly as predetermined by the form or contour of therespective cams 22 and 23. The shape of these cams is obviouslyselectedto obtain the desired resultant path of movement oi the dressing tool,which path, for illustrative purposes, may define a contour illustratedby the full line O-A-B-C-D-M in Fig. 1. Since the followers 34 and 45are constrained against oscillation, the path of movement will be thesame in both the forward and reverse operations;

To facilitate the dressing of the entire cutting contour of the grindingrib 52 by means of a single dressing tool I8, it is desirable to havethe tool cut only on the radially inward movement and to clear thegrinding rib on the radially outward movement.

Radial clearance is obtained by releasing the screw 48 to introduce apredetermined amount of lost motion between the socket 41 and thetapered tip 49, and thereby permit oscillation of the ,cam follower 45between the two extreme positions upon reversal of rotation of thecoacting cam 23. Such radial clearance is indicated at 58 in Figs. 8 and9 and results in retraction of the dressing tool radially on the returnmovement, as indicated by the path M-M'-D'-C-B'A'O'-O.

Clearance longitudinally of the grinding wheel axis is obtainable byreleasing the screw 39 to introduce lost motion between the notch 38 andthe tapered end 4I, and thereby permit limited oscillation of thefollower 34 between two extreme positions upon reversal of rotation ofthe coacting cam 22. Such longitudinal clearance is indicated at 51 inFig. 9, and results in retraction of the dressing tool for the purposeof clearing each ilank on the outward movement. The degree of clearancein each instance is determined by the degree of the lost motion, whichin turn may be varied by the extent to which the respective screws 39and 48 are retracted.

Assuming that both cam followers 34 and 45 are released for oscillatorymovement, and assuming further that the dressing cycle is initiated bystarting the drive to the shaft 2I, the respective cams 22, 23, 24 willstart to rotate in the direction of the arrow (see'Fig. 1). During thisrotation, the dressing tool I8 will move along the line O-A (see Fig.9), then outwardly along the line A--B without contacting the contiguousflank 53, then along the line B-C in the course of which it will contactand dress the truncating line 55 of the grinding rib 52, then radiallyinwardly along the line C-D to dress the ank 54, and then longitudinallyalong the line D-M. At the point M, the cam shaft 2| will have completedslightly less than one complete revolution to cause the cam 24 toactuate the switch I3.

Actuation of the switch serves to reverse the drive through the worm 23and worm wheel 25 to rotate theA cams 22, 23, and 24 in the reversedirection. Thereupon, the dressing tool I8 will describe a path ofmovement from M to M', then M' to D', then D' to C', and then'C to B'without contacting the previously dressed flank54 and truncating line55. In the continued return movement, the dressing tool I8 will movealong the line B'-A' to dress the opposed flank 53, and then along thelines A- and O'--O back to initial position. At thisl point, the cam 24will again actuate the switch 33 to interrupt the drive, and therebyterminate the dressing cycle.

It will be noted that the contour of the path of movement of thedressing tool I8 is the same in both directions of operation, but thatthe respective paths are displaced from each other both radially andlongitudinally of the grinding wheel 2 so that in one path the tool willdress one flank from the apex to the root, and in the reverse path thetool will dress the other ilank from the apex to the root. Thisseparation of the reverse paths of movement is obtained by reason of theradial and longitudinal clearances effected through oscillation of thecam followers. By varying the extent of the clearances, the width of therib can be altered without changing the included angle between theflanks. of various widths can be obtained merely by adjusting the rangeof oscillation of the cam followers 34 and 45, and upon sufficientadjustment, ribs of V form can be produced.

In the modified form of Figs. l0 and l1 two tools I8a and I8b arearranged respectively to dress the opposite anks 53c and 54a of agrinding rib 52a. The paths of movement described by the tools areillustrated in Fig. 11. Briefly,

stated, during the initial operation of the dressing mechanism in onedirection, the tool I8a will dress the flank 53 and the truncating line55a. During this movement the other tool will describe a path of similarcontour, but by reason of the longitudinal and radial clearances willnot contact the grinding rib 52a. During the reverse operation of thedressing mechanism, the tool I8b will dress the opposed flank 548, whilethe tool I8ai will clear the rib. The two tool arrangement is especiallysuitable for dressing grinding wheel ribs having a relatively smallincluded angle between the flanks.

I claim as my invention:

l. In a dressing mechanism, in combination, a support, a dressing toolholder mounted for movement in forward and reverse directions, and meansfor moving said holder, said means including a lost motion toggleconnection for causing the paths of forward and reverse movement of saidholder to be non-coincident.

2. In a dressing mechanism, in combination, a support, a dressing toolholder adapted to support a dressing tool and mounted for movement inforward and reverse directions, means for actuating said holder totranslate said dressing tool, and pivotal means adapted to occupy oneextreme position during movement of said dressing tool in one directionand another extreme position during movement of said dressing tool inthe other direction, whereby to cause said tool to describe spaced pathsof movement.

3. In a dressing mechanism, in combination,

a support, a holder adapted to carry a dressing' tool and being mountedin said support for reversible movement, and means including a camcoacting with said holder to move said dressing tool through a path ofpredetermined contour, said last-mentioned means including a pivotal camfollower adapted for reverse oscillation into opposite extreme positionsupon reverse move- Consequently, truncated rib forms ment of said cam,and means selectively available for locking said follower againstpivotal -movement or varying the degree of said pivotal movement.

4. In a dressing mechanism, in combination, a body housing, a supportingmember mounted for rectilinear movement within said housing, a toolholder mounted on said supporting member for movement therewith and forindependent movement in a direction perpendicular thereto, a rotary cammounted on said member, a pivotal cam follower mounted on said holderand coacting with said cam, said follower being automatically reversibleupon reverse movement of said cam whereby to adjust the relationshipbetween said cam and said holder, and a dressing'tool carried by saidholder.

5. In a dressing mechanism, in combination. a main body, a first slidemounted on said body for movement in one direction, a second slidemounted on said first-mentioned slide for movement in an inclineddirection andv carrying a dressing tool, and reversible drive meansmounted on said first 'slide for reciprocating said second slide andincluding a lost motion drive connection with said second slide forcausing said dressing tool to describe a predetermined cutting path inone direction of movement and on reverse movement to occupy a retractedposition.

6. In a dressing mechanism, in combination, a housing, a support in saidhousing, a rotary reversible drive cam mounted on said support. a toolslide mounted on said support for reciprocation radially of said cam, apivotal follower mounted on said slide and coacting at its free end withsaid cam, a tapered recess in said follower, a tapered detent adjustableon said slide for engagement in said recess to provide a lost motionresulting in oscillation of said follower into diil'erent angularrelations to the radius upon reverse movement of said cam, whereby toadvance or retract said slide relative to said cam, and a dressing toolmounted for movement with said slide.

7. In a dressing mechanism, in combination, a support, a first slidemounted on said support for rectilinear movement in one direction, asecond slide mounted on said first slide for rectilinear movement in aninclined direction, a dressing tool supported by said second slide,reversible drive means for reciprocating said rstmentioned slide,reversible drive means for reciprocating said second-mentioned slide onsaid rst-mentioned slide in timed relation to said first-mentionedslide, whereby to cause said dressing tool to describe a resultant path,each of said drive means including a lost motion connectionautomatically operable as an incident t0 reversal to adjust the positionof the associated slide in relation to the associated drive meanswhereby said tool is caused to move in a predetermined path in onedirection and in a different path in the reverse direction.

8. In a dressing mechanism, in combination, a housing, a slide mountedin said housing for reversible movement. a dressing tool carried by saidslide, a rotary drive cam carried by said slide, an oscillatory camfollower mounted in said housing and coacting with said rotary cam, andspring means acting on said slide to maintain said cam in operativeengagement with said follower, said follower being reversibly movable asan incident to reversal of said cam whereby to adjust the position ofsaid slide in relation to the angular phase of said cam.

9. In a dressing mechanism, in combination, a

housing, a slide mounted within said housing forY reverse movement, adressing tool operatively associated with said slide for actuationthereby, and means including a rotary cam and coacting cam follower forreciprocating said slide, said cam -follower being pivotal in oppositedirections as an incident to reversal of said cam whereby to vary thecenter distance between said cam and the pivot of said follower.

10. In a dressing mechanism, in combination,- a housing, a slide mountedfor reverse movement on said housing, a dressing tool operativelyassociated with said slide for actuation thereby in reverse directions,a rotary cam mounted on said slide, a cam follower pivotally mountedintermediate its ends on said .housing and coacting at one end with saidcam, spring means acting to maintain said cam in operative engagementwith said follower, the other end of said follower being formed with atapered recess, and a screw adjustably supported in said housing andhaving a complementa] tapered end adapted to project adjustably intosaid recess whereby to permit a limited degree of oscillation of saidfollower upon reversal of said cam.

11. In a dressing mechanism, in combination, a housing,a main slidesuspended in said housing for rectilinear reciprocation, a second slidesupported on said main slide for movement therewith and forreciprocation thereon in a generally transverse direction, a dressingtool carried by.

said second slide, a shaft journaled in said main slide, a worm and wormwheel drive for rotating said shaft in reverse directions, meansincluding a rotary cam on said shaft and a coacting follower in saidhousing for reciprocating said main slide in a back and forth movementupon rotation of said shaft, and means including a cam on said shaft anda coacting follower on said second silde for reciprocating said secondslide in timed relation to the reciprocation of said main slide.

12. In a dressing mechanism, in combination, a support, a dressing toolholder mounted for movement in forward and reverse directions andcarrying two spaced dressing tools, and means for moving said holder,said means including a lost motion toggle connection for causing thepaths of forward and reverse movement of said holder to benon-coincident.

13. In a dressing mechanism, in combination, a support, a tool holdercarrying two oppositely disposed tools in ilxed relationship withrespect to each other and adapted for dressing opposite sides of theperiphery of a rotary grinding wheel, a slide assembly for supportingsaid holder for movement in a predetermined resultant path, and meansfor actuating said slides in reverse directions and including lostmotion means operable in one direction of movement to move one of saidtools through a cutting path while maintaining the other of said toolsin a retracted position and in the other direction of movement to movethe other of said tools in a cutting path while maintaining thefirst-mentioned tool in a retracted position.

14. In a dressing mechanism, in combination, a support, a tool holdermounted for reverse movement on said support and carrying a singledressing tool for dressing opposite side flanks of the periphery of acutting rib on a grinding wheel, and means for actuating said tool andincluding lost motion means automatically oper-A able as an incident toreversal of movement of said tool, whereby to cause said tool in onedirection of movement to clear one of said flanks and to dress the otherof said flanks and in the other direction of movement to clear saidother flank and to dress said first-mentioned flank.

15. In a dressing mechanism, in combination, a support, a tool holdermounted for reverse movement on said support and carrying a singledressing tool for dressing opposite side flanks of the periphery of acutting rib on a grinding wheel, means for actuating said tool andincluding lost motion meansautomatically operable as an incident toreversal of movement of said tool, whereby to cause said tool in onedirection of movement to clear one of said flanks and to dress theotherof' said flanks and in the other direction i' movement to clear saidother flank and to dress said first-mentioned flank, and means foradjusting the degree of lost motion whereby to adjust the extent of saidclearance.

16. In a dressing mechanism, in combination, a support, a tool holdercarrying a dressing tool for dressing opposite flanks of a tapered ribon the periphery of a grinding wheel, and means for actuating saidtool'successively in opposite directions to describe a predeterminedpath of movement in one direction and a like path but spaced from saidfirst mentioned path in a reverse direction respectively to dress theopposite flanks.

17. In a dressing mechanism, in combi-nation, a support, a tool holdermounted on said support and carrying a dressing tool, means forreversibly driving said dressing tool through a path which extendsacross the opposite flanks of a grinding wheel to be dressed, saiddriving means including lost motion means effective at each reversal oftool movement to cause the tool when moving in one direction to dressone flank and clear the opposite flank, and when moving in the oppositedirection to clear said one flank and dress said opposite flank.

18. In a dressing mechanism, in combination, a support, a first slidemounted thereon for movement in one direction, a second slide mounted onsaid first slide for movement in an inclined direction, a dressing toolcarried by said second slide, reversible driving means for reciprocatingboth slides in their respective directions whereby the path described bysaid tool willA be the resultant of both slide movements, said drivemeans including a lost motion drive connection to each slide for causingthe tool to describe different paths as it moves in opposite directions.

19. In a dressing mechanism, in combination, a support, a first slidemounted thereon for movement in one direction, a second slide mounted onsaid first slide for movement in an inclined direction, a dressing toolcarried by said second slide, reversible drive means for reciprocatingboth slides in their respective directions whereby the path described bysaid tool will be the resultant of both slide movements, said drivemeans including a lost motion drive connection to each slide for causingthe tool to describe different paths as it moves in opposite directions,and means for independently adjusting the extent of lost motion in theconnection to each slide.

HAROLD N. SEYFERTH.

